The present invention relates to optical pickup devices, and optical disc devices to which the optical pickup devices are mounted.
Conventionally, semiconductor lasers are widely used as light sources of optical pickup devices. However, some semiconductor lasers exhibit high astigmatism. If such a semiconductor laser is used in the optical pickup device without correcting the existing astigmatism, a diameter of a beam spot on an optical disc cannot be substantially reduced, and therefore it is difficult to enhance performance (for example, reproduction performance) of the optical pickup device. Therefore, it has been proposed to set a tilt angle of a lens provided in an optical path so as to correct the astigmatism of the semiconductor laser (see, for example, Patent Document Nos. 1 and 2).
At present, typical optical pickup devices can perform reproduction of CD (Compact Disc), DVD (Digital Versatile Disc) and BD (Blu-Ray Disc). Such an optical pickup device has a plurality of semiconductor lasers, and is configured so that laser beams emitted by respective semiconductor lasers share a common optical path, in order to achieve miniaturization of the optical pickup device.    Patent Document No. 1: Japanese Laid-open Patent Publication No. S59-58414    Patent Document No. 2: Japanese Laid-open Patent Publication No. H8-147747
However, if a tilt is given to the lens in the optical path of the optical pickup device having the plurality of semiconductor lasers, correction of astigmatism of a laser beam with low astigmatism (i.e., a laser beam which need not be corrected) is performed, as well as the correction of a laser beam with high astigmatism. For this reason, it is difficult to suitably reduce astigmatism of all of the laser beams emitted by the respective semiconductor lasers, and it is therefore difficult to enhance reproduction performance of the optical pickup device.